


What You Did Last Night

by Iolite666



Series: Cummies [2]
Category: Pocket Monsters | Pokemon - All Media Types, Pocket Monsters: Sword & Shield | Pokemon Sword & Shield Versions
Genre: F/M, Implied Voyeurism, Loss of Virginity, Penis In Vagina Sex, Riding, Sibling Incest, well marnie overheard piers jerking it
Language: English
Status: Completed
Published: 2020-04-07
Updated: 2020-04-07
Packaged: 2021-03-02 02:14:38
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 1,156
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23527480
Author URL: https://archiveofourown.org/users/Iolite666/pseuds/Iolite666
Summary: Marnie takes advantage of the fact she now knows that her brother feels the same way about her as she does him. After he comes home and flops down on the sofa, she enacts her plan and confronts Piers about what she heard last night, and things escalate.
Relationships: Mary | Marnie/Nezu | Piers
Series: Cummies [2]
Series URL: https://archiveofourown.org/series/1657999
Comments: 1
Kudos: 29





	What You Did Last Night

**Author's Note:**

> a commission from nerunerunii on twitter! i love writing these two and im glad i got the chance to flex my writing muscles with them, taking a break to write some of my fave siblings between uni work is a blessing

“Hey, Marn? I’m home!” Piers threw his keys into the dish they kept by the door of the flat, missed by several feet, and stood and stared as they clattered loudly to the floor. He walked past without picking them up, too tired to begin to argue with his inanimate possessions. He flopped himself down on the living room sofa, and sighed. Spikemuth had never been on the radar before like it was now, after his whole involvement with the mess that was the runaway dynamax pokemon, and he was glad that he would be retiring from his role of gym leader soon. Though, he worried for Marnie, could she handle the spotlight? Sure, she had blasted through the championship and had only lost to the challenger from Postwick that wasn’t Hop, but being a leader was a whole different kettle of fish.

Speak of the devil, Piers mused, as he heard Marnie stomp down the stairs from her bedroom. God, she was so cute, he loved her so much, (a little _too_ much, that traitorous, nasty side of his brain whispered), the way she handled herself was amazing and he was constantly in awe of his little sister. He figured it was a bit weird that he looked up to her, but fuck it, he’d always done things a little strangely. 

“Piers.” Uh-oh. Was Marnie upset with him? She _never_ called him by his name in that flat tone if she could help it. Sitting up from his reclined position, she was staring at him intently over the back of the sofa, arms folded, _pushing up her cute, perky tits so nicely-_ God, he wanted to fucking chop his hands off, the way they itched to grope his little sister, of all fucking people. 

“Uh, yeah? What’s up, Marn?” His cock was half-hard. By god he hoped she didn’t notice the way she affected him. He was wrong, sick, he wanted to fuck his little sister.

“I heard you last night.” With that, Piers’ stomach turned to ice and rolled, his face paled and his eyes widened. Surely not. Surely fucking not, she hadn’t heard him pawing at his cock to the thought of her mouth, her tits, her pussy. He had to play it cool.

“Whatcha mean? I came home and went to bed last night.” Piers kept his eyes on Marnie as she rounded the end of the sofa to stand by him.

She huffed at him. “Yeah, but I heard what ya did after you went to bed.” Piers’ eyes bugged out, but she didn’t let him interrupt, “You jerked off ta me, right? Heard you tugging on your cock and moanin’ my name, big bro...” Marnie was practically purring at him and Piers lay still, shocked to his core. She didn’t sound disgusted, nor angry. If anything, she sounded… _turned on_.

“Marn, what-” With little fanfare, Marnie clambered onto the sofa above him, and settled herself in his lap, right above his cock, which had fully hardened and was throbbing in the tight spandex of his gym uniform, the fucking traitor.

Though, “Ohhh, fuck,” the way Marnie rolled her hips into his, clumsy and shaky, had him thinking that his cock wasn’t being traitorous, but was just reacting to how _hot_ Marnie was.

“I want you, Piers.” she said, and rolled her hips again. Her voice dropped to a mumble, “want you so fucking much, thought about it for so long… jerked off just thinkin’ about it.”

His lower stomach blazed with arousal, and his cock throbbed a wet spurt of pre-cum into his uniform. Fuck. Marnie began tugging at this belt, and mind thoroughly gone in a haze of horny heat, Piers simply lifted his hips and let her strip his lower body. His cock slapped against the spandex of his shirt, and Marnie gasped.

“Mm, you’re big. Will it fit?” Will it? He honestly had no fucking clue, he’d never done this before and that question alone solidified the fact Marnie hadn’t either.

“Marn, maybe, maybe we shouldn’t? Neither of us have ever-”

“I _want_ this and you’re not gonna stop me unless you don’t want it.” Marnie’s tone brooked no argument, and Piers settled back into the sofa as she kneeled above him for a second and fiddled with something under her skirt. He heard the sound of a small latch, and it clicked. Lingerie that fastened over her cunt. His sister was wearing lingerie and he was going to fuck her.

The first slide of her hot, wet cunt along the length of his cock had him hissing as his head thumped back onto the arm of the chair. She lifted herself over him, and he realised what she was about to do. “Marn! I need to prep you, make sure I don’t hurt you-” and before he could say another word, his cock was engulfed in divine heat. Fuck, she was clenching around him as she sunk down and she was so hot, wet, alternating between an easy slide and a tight grip.

“Ah, oh, are you- are you okay, Marn?” She lifted herself up and the cold of the apartment air compared to her cunt made him hiss, and slid back down, prompting a moan from both of them.

“Shut- shut up, Piers, I can take this, I can do it.” She let out a shaky breath as she started up a rhythm of bouncing on his cock, her hips meeting his as she fully sheathed him inside of her. The what was building, electric zaps of pleasure travelling from her cunt, up her spin, settling as suffused warmth across her body, and the way Piers’ cock twitched inside her, she knew they both wouldn’t last long. They were each other’s firsts in so many ways.

As she sat back down on his cock she leaned forwards and placed a chaste kiss on her brother’s lips that wouldn’t remain so for long. Lips opened and tongues teased, they sighed moans into each other’s mouths as their pleasure crescendoed, their rhythm losing all balance and co-ordination, turning into the desperate fuck it inevitably would’ve become.

“Fuck- fuck, Marn, I can’t, please, I’m gonna cum!” Marnie gasped and slammed her hips down one last time and trembled atop of Piers, her cunt fluttering and clenching around his cock as her orgasm washed white over her body and brain. Piers followed suit, his hips bucking up once, twice, three times as the wave of his orgasm dragged him under the depths of pleasure, cum coating the inside of Marnie’s cunt.

They both sighed as their highs receded. Intense pleasure settled into intimate warmth.

“I didn’t hurt ya, did I?” Piers mumbled into Marnie’s lips, and for his efforts he got a scoff and a smile.

“Nah.” Marnie settled her head on his chest, still warming his softening cock inside of her. “Love you, Piers.”

“Love ya too, Marn.”

**Author's Note:**

> come scream at me about problematic content on [twitter](https://twitter.com/sonwifeseliph)!


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